Apparatus and methods for conduits and materials

ABSTRACT

The present invention provides apparatus and methods for a conduit, such as an implantable conduit for a vessel. The conduit may comprise a main member and a side-branch member. The conduit may be implanted with the side-branch member initially disposed within the main member. When positioned, the side-branch member may then be extended from within the main member and into a vessel side-branch. The materials for the conduit may include circumferentially distensible and/or low recoil materials. The materials for the conduit may be constructed by various techniques and may include materials with enhanced flexibility and kink resistance.

RELATED APPLICATION INFORMATION

This application claims the benefit of and is a continuation of U.S.application Ser. No. 14/463,340, filed on Aug. 19, 2014, whichapplication claims the benefit of and is a continuation of U.S.application Ser. No. 12/951,433, filed on Nov. 22, 2010, whichapplication claims the benefit of U.S. Provisional Application No.61/265,527, filed on Dec. 1, 2009, and also claims the benefit of and isa continuation-in-part of U.S. application Ser. No. 11/199,717, filed onAug. 9, 2005, which application is a continuation of U.S. applicationSer. No. 10/071,635, filed on Feb. 7, 2002 (now U.S. Pat. No.6,949,121), each of which is incorporated herein by reference in itsentirety.

BACKGROUND

The following disclosure generally relates to medical devices.

Vascular disease, the disease of blood vessels, is one of the leadingcauses of death in the western world. There are two main categories ofvascular disease, aneurysmal and occlusive. Aneurysmal disease resultsin the weakening of blood vessels causing them to dilate excessively andin some instances ultimately rupture. Occlusive disease results inblockage of blood vessels, limiting the conveyance of blood.

Stents and stent-grafts are commonly used to treat diseased bloodvessels and other tubular structures within the body. Stents andstent-grafts have been employed successfully to either reinforceafflicted blood vessels in the case of aneurysmal disease, or toradially open and support blood vessels for the purpose of restoringblood flow in the case of occlusive disease. To such ends, stents andstent-grafts have been implanted in the coronary as well as peripheralvasculature. Additionally, stents have been implanted within theneurovasculature, and in other bodily conduits such as the urinarytract, the bile duct, and the tracheo-bronchial tree.

Current stent-grafts intended for the treatment of aneurysmal diseaseare generally available in various diameters. Several devices areavailable in bifurcated configurations. These bifurcated devices aretypically designed for use within the aortic bifurcation, where theabdominal aorta branches into the right and left common iliac arteries.Frequently, this anatomic region is riddled by aneurysmal disease,causing a potentially life-threatening situation. In an effort to treatthe potentially life-threatening situation, bifurcated stent-grafts areimplanted within the aneurysmal regions of the afflicted to vessels,essentially forming a new blood flow conduit within the aneurysm, andisolating the aneurysm from blood flow and the associated bloodpressure. This is referred to as excluding the aneurysm. Similarly,aneurysms of the aortic arch and the thoracic aorta are also common.

Conventional stent-grafts, however, do not accommodate side-branches ofthe aorta. Once an aneurysm has been excluded, the entire diseasedsection of the afflicted vessel is isolated from normal blood flow. Thisisolation includes any side-branches emanating from the aorta within theafflicted region. While this may be a good outcome from the perspectiveof managing a potentially life-threatening situation, such isolationfrom blood flow can lead to ischemic complications in certain areas ofthe body. For example, emanating from the abdominal aorta distal to therenal arteries are lumbar arteries, testicular/ovarian arteries, and theinferior mesenteric artery, which provides blood to the left transversecolon, descending and sigmoid colons, and rectum. Many aneurysms of theabdominal aorta include the origin of the inferior mesenteric artery.After successful exclusion of these aneurysms, the left transversecolon, descending and sigmoid colons, and rectum rely on collateralcirculation for their blood supply. For many patients, the collateralcirculation is sufficient, but for others it is not, resulting incomplications involving the various organs.

Additionally, many aorto-iliac aneurysms involve the abdominal aorta aswell as substantial portions of either (or both) of the common iliacarteries. In many cases, the disease extends along the common iliacartery past the bifurcation point where the common iliac branches intothe external and the internal iliac arteries. In such cases, theendoluminal treatment of the aneurysm may require extending thestent-graft device into the external iliac artery, isolating theinternal iliac artery from normal blood supply and leaving largeportions of the pelvic area and leg reliant on collateral circulationfor their blood supply. For example, the hypogastric artery, whichsupplies blood to the pelvic area, branches from the internal iliacartery. Isolation of the hypogastric artery from normal blood flow canresult in buttock claudication, impotence, and colon ischemia.

Aneurysms of the aortic arch, for example, can be especially difficultto treat using currently available stent-graft devices. Three majorvessels originate from the aortic arch: the brachiocephalic, the leftcommon carotid, and the subclavian artery. These vessels providecritical blood flow to the head, neck and arms. If a stent-graft deviceis endoluminally implanted to treat aortic arch aneurysms, adjunctivemeasures must be taken to ensure adequate blood supply to the body parts(especially the brain) that receive their blood supply from the affectedvessels.

On the other hand, while in some instances isolation of a side-branchvessel via aneurysm exclusion results in compromised blood supply due toinadequate collateral circulation, in situations of abundant collateralcirculation, the presence of a side-branch vessel can actually hinderaneurysm exclusion. Retrograde blood flow from side-branches emanatingwithin the aneurysmal region can maintain blood pressure within theaneurysm, often resulting in leakage between the stent-graft device andthe afflicted vessel.

Like stent-grafts intended for the treatment of aneurysmal disease,stent-grafts intended for the treatment of occlusive disease aregenerally tubular and available in various diameters. Such stent-graftdevices offer the advantage of providing a physical barrier, whichimpedes reproliferation of the disease through the wall of the implanteddevice. The treatment of vessels afflicted by occlusive disease atpoints of bifurcations, however, can be problematic due to theunpredictability of the vascular remodeling associated with balloonangioplasty and stent-graft implantation. In many instances,side-branches can be compromised as a result of plaque redistributionfrom the main vessel into the origin of the side-branch, resulting instenosis of the side-branch.

SUMMARY

A prosthetic conduit according to various described embodiments includesa main member and a side-branch member. The main member may beconfigured to reside in a main vessel. For example, one embodimentcomprises at least one stent, at least one main graft, and at least oneopening in its side wall. The side-branch member is suitably configuredto reside in a side-branch vessel, and may include, for example, atleast one side-branch stent and at least one side-branch graft. Theside-branch member is connected to the main member at the side wallopening. The side-branch member may be configured to be extendablethrough the opening to deploy the stent-graft.

The side-branch member may be located within the main member before andduring delivery of the stent-graft to a desired location within avessel. Once the main member is placed in a desired location, theside-branch member may be pushed or pulled out of the main member andinto the desired side-branch vessel. The stent-graft may be insertedinto a vessel at one access site and placed at a desired location withinthe vessel by any suitable method, such as using balloon catheters,guidewires, and/or a constraining sheath with a push tube.

Materials according to various aspects of the described embodiments thatmay be used in the main member, the side-branch member, and/or otherelements are distensible. In this regard, exemplary embodiments providecharacteristics such as enhanced flexibility, kink resistance, and/orlimited foreshortening. By way of example only, the materials may betreated to circumferentially distend without significant foreshorteningand/or recoil while other forms of manipulation may be employed toimpart improved flexibility.

BRIEF DESCRIPTION OF THE EXEMPLARY DRAWINGS

Additional aspects of the disclosed embodiments will become evident uponreviewing the non-limiting descriptions set forth in the specificationand claims, in conjunction with the accompanying figures, wherein likenumerals designate like elements and wherein:

FIG. 1 is a perspective view of an exemplary embodiment of a prostheticconduit with a side-branch shown within a cross-section of a vessel witha side-branch.

FIG. 2 is a perspective view of an exemplary embodiment of a main memberof a prosthetic conduit.

FIG. 3 is a perspective view of an exemplary embodiment of a side-branchmember.

FIG. 4 is a cross-sectional view of an exemplary embodiment of aprosthetic conduit, shown with an apparatus for delivery, including amain guidewire, a main balloon catheter, a side-branch guidewire and aside-branch balloon catheter.

FIG. 5 is a flow chart illustrating an exemplary delivery and deploymentprocess.

FIG. 6 is a perspective view of an exemplary embodiment of a prostheticconduit, with the distal end of the main member inflated by a ballooncatheter and the side-branch retracted, shown within a cross-section ofa vessel with a side-branch.

FIG. 7 is a cross-sectional view of an exemplary embodiment of aprosthetic conduit, with the distal end of the main member inflated witha balloon catheter and the side-branch member partially pushed out fromwithin the main member.

FIG. 8 is a perspective view of an exemplary embodiment of a prostheticconduit, shown within a cross-section of a vessel with a side-branch,with the main member fully expanded and the side-branch member not fullyexpanded.

FIG. 9 is a cross-sectional view of an exemplary embodiment of aprosthetic conduit with a deployment tube.

FIG. 10 is a cross-sectional view of an exemplary embodiment of aprosthetic conduit wherein the main member is self-expanding, shown withan apparatus for delivery including a constraining sheath, a push tube,a side-branch balloon catheter, and a side-branch guidewire.

FIG. 11 is a cross-sectional view of an exemplary embodiment of thedistal end of a constraining sheath configured to deliver a prostheticconduit with a self-expanding main member within a vessel.

FIG. 12 is an end-on view of the distal end of an exemplary embodimentof the constraining sheath used to deliver a prosthetic conduit with aself-expanding main member within a vessel.

FIG. 13 is a cross-sectional, end-on view of an exemplary embodiment ofa push tube device configured to deliver a prosthetic conduit with aself-expanding main member within a vessel.

FIGS. 14A-B are a flow chart illustrating an exemplary preparationprocess for a prosthetic conduit.

FIG. 15 is a graph illustrating distensibility data for a distensibletube and a non-distensible tube.

It is to be noted that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help to improve understandingof embodiments of the present invention.

DETAILED DESCRIPTION

Various aspects and features disclosed hereinafter may be described interms of functional components and steps. Such functional components andsteps may be realized by any number of elements and/or steps configuredto perform the specified functions. For example, the present methods andapparatus may employ conduits and supports, like grafts and stents,which may carry out a variety of functions in various embodiments,applications, and environments. In addition, the present methods andapparatus may be practiced in conjunction with any number of proceduresand systems, and the apparatus and methods described are merelyexemplary applications. Further, the present methods and apparatus mayemploy any number of techniques, conventional or otherwise, forplacement, use, manufacturing, and the like. Such general techniquesthat may be referred to are not described in detail.

A prosthetic conduit system according to various aspects of thedisclosed embodiments is implantable within an organism, such as a humanbeing or animal. The prosthetic conduit may comprise any conduit, forexample for use in blood vessels, bile ducts, the urinary tracts, or anyother conduit in the organism. For example, a prosthetic blood vesselstructure may comprise a stent, a graft, a stent-graft, or otherimplantable structure. The prosthetic blood vessel may be configured,however, in any manner according to the particular application orenvironment, including variations in dimensions, shape, materials,flexibility, and the like. Various aspects of the disclosed embodimentsmay also be applicable to other devices, such as other medical devicesand other conduits.

Referring to FIG. 1, a prosthetic conduit system 100 according tovarious aspects of the present invention includes a prosthetic conduit102, such as a stent-graft. In various embodiments, the prostheticconduit 102 includes a side-branch, and is suitable for placement in amain vessel 108 with a side-branch vessel 110. For example, the toprosthetic conduit 102 may include a main member 104 and a side-branchmember 106. Each of the main member 104 and the side-branch member 106may include one or more stents and one or more sections of graftmaterial.

Although the present exemplary embodiment comprises the stent-grafthaving one main member 104 with one side-branch member 106, the variousconfigurations of a prosthetic conduit are not so limited, and may beconfigured in any suitable manner for the particular application and/orenvironment. For example, the main member 104 may have a bifurcation atone or both ends, two or more side-branch members 106 may be included,and the like. The prosthetic conduit 102 may include one continuouspiece of graft material and multiple stents, one continuous stent-graft,or any suitable combination of one or more stents and/or one or morepieces of graft material. Furthermore, the side-branch member 106 may beconfigured to branch from the main member at any suitable angle. Theside-branch member 106 may be further configured to adapt to a range ofangles to allow for placement into multiple different configurations ofmain vessel 108 and side-branch vessel 110.

Similarly, the prosthetic conduit 102 may have any suitable size orcombination of sizes. For example, the main member 104 may be configuredfor placement within a relatively large main vessel 108, such as theabdominal aorta, while side-branch member 106 may be configured forplacement within a relatively small side-branch vessel 110, such as arenal artery. In another embodiment, both the main member 104 andside-branch member 106 may be relatively small, for example if theprosthetic conduit is configured to be placed in human coronaryarteries. Thus, the prosthetic conduit 102, including the main member104 and side-branch member 106, may have any suitable dimensions.

In a first exemplary embodiment, the entire length of the main member104 comprises a combination of stent and graft material, while theside-branch member 106 includes a graft material along its entire lengthwith a side-branch stent 112 located at its distal end. In anotherembodiment, each of the main member 104 and the side-branch member 106comprises a single continuous piece of graft material and multiplestents. Alternatively, the prosthetic conduit 102 may comprise onecontinuous stent-graft comprised of a single graft and a single stent.Further, the prosthetic conduit 102 may comprise one or more grafts withno stents or one or more stents with no graft sections. Thus, theprosthetic conduit 102 may comprise various combinations of one or morestents and one or more pieces of graft material.

Referring now to FIG. 2, the main member 104 may be configured toprovide a main blood flow conduit and may include a support for theconduit to keep it open. Further, the main member 104 may be configuredto provide flow to and/or from the side-branch member 106. In thepresent embodiment, the main member suitably has a generally tubularconfiguration with open ends, and comprises a main stent 200, a maingraft 202, and at least one side opening 204. The main stent 200provides support to maintain the desired position and/or configurationof the prosthetic conduit 102. The main stent 200 may be a single stentor a plurality of stents, and may be present along the entire length ofthe main member 104, or only in sections, and may extend beyond thelength of the main graft 202. The main stent 200 may be incorporatedinto the main member 104 in any location by any suitable method, or maybe installed separately. The main stent 200 may be deployed in anyappropriate manner, such as balloon expansion, self-expansion, or anysuitable combination of both, and may be constructed of a variety ofmaterials or combinations, such as, but not limited to, metals or alloys(stainless steel, titanium, tantalum, nitinol and the like), polymers,carbon, ceramics and the like.

Alternative embodiments of the main member 104 may also include other oradditional mechanisms for supporting and/or securing the main member 104to a surrounding organism vessel 108. Stents or other suitable devices,for example, may be utilized to provide additional support and/orstrength to the main member 104, such that the main stent 200 may besupplemented, replaced, or omitted altogether. Further, the main member104 may be secured in position by an adhesive on at least a portion ofthe main member 104 outer surface (or the inner surface of theattachment site), a set of barbs or pins attached to the main member 104and engaging the surrounding tissue, and the like.

The main graft 202 provides a conduit for fluid flow through the mainmember 104. The main graft 202 may be comprised of any suitablematerial, such as a biocompatible material, or combination of materials,such as, but not limited to, polyester, polyether sulfone, polyethylene,polytetrafluoroethylene (PTFE), polyurethane and the like. Further, thematerials may be configured or treated in any manner to achieve selectedcharacteristics. For example, the material may be treated in accordancewith the disclosure of U.S. Pat. No. 5,800,522, issued Sep. 1, 1998, toCampbell, et al. Moreover, the main graft 202 may be comprised ofvarious forms or combinations of forms, such as, but not limited to,extruded tubing, braided tubing, textile tubing, tubing created from thewrapping and bonding of thin films, and the like. The main graft 202 maybe of any suitable porosity.

In the present embodiment, the main graft 202 includes a thin, flexiblematerial, such as polyethylene. In the present embodiment, the maingraft 202 is not treated, as described below, to be circumferentiallydistensible. The main graft 202 may, however, comprise any suitablematerial, including a material that may be distended with minimalforeshortening and recoil to conform to the organism vessel 108, 110,the stents 112, 200, or other characteristic. If the main graft 202material is distensible (for example, as described and defined in U.S.Pat. No. 5,800,522, issued Sep. 1, 1998, to Campbell, et al.), the graftmaterial may be circumferentially distended along its entire length, orin selected portions. Various coatings or treatments can be applied toeither the main stent 200, the main graft 202, or both, to render themain member 104 more biocompatible (pyrolytic carbon, hydrogels and thelike) and/or to provide for the elution of drugs (heparin, anti-plateletagents, platelet derived growth factors, antibiotics, steroids and thelike). Additionally, various coatings or treatments may be applied toeither the main stent 200, the main graft 202, or both, to render themain member 104 radioactive.

The main graft 202 may be configured to be placed on either the innersurface or the outer surface of the main stent 200, or in any suitableposition relative to the inner or outer surface of the main stent 200.The main stent 200 and main graft 202 may be connected before placementinto a vessel, or the main stent 200 and main graft 202 may be insertedinto a vessel separately and connected within the vessel. In eithercase, the main graft 202 may be attached to the main stent 200 by anysuitable mechanism. Certain embodiments of the main member 104 may bemanufactured by a lamination process so that the material of the maingraft 202 covers both the inner and outer surfaces of the main stent200.

The main member 104 may include a radiopaque material to enhance thevisibility of the main member 104. For example, the main stent 200 orthe main graft 202 may be wholly or partially comprised of radiopaquematerials. Alternatively, radiopaque markers 206 may be incorporatedinto the main graft 202 or the main stent 200, either throughout thestructure or at one or more locations.

The side-branch member 106 facilitates flow between the main member 104and a side-branch vessel 110. For example, referring to FIG. 3, theside-branch member 106 may have a generally tubular configuration withan open proximal end 308 and an open distal end 306. The side-branchmember 106 suitably comprises a side-branch graft 310 for facilitatingfluid flow between the main member 104 and the open distal end 306. Theside-branch member 106 may also include a side-branch stent 112, forexample to support the distal end 306. In the present exemplaryembodiment, the side-branch member 106 includes a straight section 300,a conical section 302, and an attachment area, such as a flange 304.

Similar to the main member 104, the side-branch member 106 may suitablycomprise a combination of one or more stents, such as the side-branchstent 112, and one or more sections of graft material, such as theside-branch graft 310. The side-branch member 106 may include anysuitable combination of stents (if desired) and graft material. Forexample, one or more stents may be used in one side-branch member 106,and/or stents may be placed entirely within the length of theside-branch graft 310 or may extend beyond the length of the side-branchgraft 310, protruding further into the side-branch vessel 110.

The side-branch stent retains the side-branch graft 310 in an openposition and/or secures the position of the side-branch graft 310. Theside-branch stent 112 may be positioned in any suitable manner, such asby placing the stent in a desired position and expanding the stentwithin the organism vessel 110. The side-branch stent 112 may be balloonexpandable, self-expanding, or any combination, and may be constructedfrom one or more of a variety of suitable materials, such as, but notlimited to, metal or alloys (stainless steel, titanium, tantalum,nitinol and the like), polymers possessing varying degrees ofbioabsorbtion and biodegradation, carbon, ceramics, and the like.

The side-branch stent 112 may be configured such that it is in contactwith the inner or outer surface of the side-branch graft 310 or acombination of both. The side-branch stent 112 may engage or be attachedto the side-branch graft 310 in any appropriate manner. For example, inone embodiment, the side-branch stent 112 may be inserted into a vesselas a separate piece and may be attached to the side-branch graft 310within the side-branch vessel 110. In other embodiments, the side-branchstent 112 is configured to be implanted at the same time as theside-branch graft 310.

The side-branch graft 310 may be constructed from one or more of avariety of suitable materials, such as, but not limited to, polyester,polyether sulfone, polyethylene, polytetrafluoroethylene, polyurethaneand the like. The side-branch graft 310 may be of any suitable porosity.In the present embodiment, the side-branch graft 310 includes a thin,strong, flexible, and/or kink resistant material. For example, theside-branch graft 310 suitably includes a material, such as treatedpolyethylene, that may be circumferentially distended withoutsignificant foreshortening and/or recoil. The graft material may becircumferentially distensible along its entire length, or in selectedportions. Further, the materials may be configured or treated in anymanner to achieve selected characteristics. For example, the materialmay be treated in accordance with the disclosure of U.S. Pat. No.5,800,522, issued Sep. 1, 1998, to Campbell, et al. Furthermore,side-branch graft 310 may be comprised of various forms or combinationsof forms, such as, but not limited to, extruded tubing, braided tubing,textile tubing, tubing created from the wrapping and bonding of thinfilms, and the like.

Various coatings or treatments may be applied to render the side-branchstent 112 and/or the side-branch graft 310 more biocompatible (pyrolyticcarbon, hydrogels and the like) and to provide for the elution of drugs(heparin, anti-platelet agents, platelet derived growth factors,antibiotics, steroids and the like). Various coatings or treatments maybe applied to render the side-branch stent 112 and/or the side-branchgraft 310 radioactive. Further, the side-branch member 106 may includeone or more areas, such as portions of the graft 310 and/or theside-branch stent 112, that are radiopaque. For example, the side-branchstent 112 may be constructed from one or more radiopaque materialsand/or one or more radiopaque markers (not shown) may be placed on thegraft 310 or the side-branch stent 112 materials at one or morelocations along the side-branch member 106.

The side-branch member 106 is connected to the main member 104 to allowfluid flow between the two components. The side-branch member 106 issuitably connected via its proximal end 308 to the side opening 204 ofthe main member 104. In the present embodiment, the conical section 302has a diameter that is larger at the proximal end 308 and tapers as itapproaches the straight section 300. The proximal end 308 may beconfigured to fit within, around, or in any other suitable configurationwith the side opening 204 of the main member 104.

The proximal end 308 may further include a mechanism, such as theattachment area including the flange 304, for facilitating attachment ofthe side-branch member 106 to the side opening 204 of the main member104. The flange 304 may be bonded in any appropriate manner to the outersurface, the inner surface, or any other appropriate portion of the mainmember 104. The flange 304 may be incorporated into the proximal end 308to provide a surface that may be easily positioned against and bonded tothe perimeter of the side opening 204, for example to effect aliquid-tight and strong connection.

The side-branch member 106 may be configured for attachment to the mainmember 104 at any suitable angle. The prosthetic conduit 102 may beprovided in multiple angular and structural combinations, enabling avariety of configurations. Furthermore, the side-branch member 106, or aportion thereof, may be configured to allow flexibility, such thatprosthetic conduit 102 may be used in a variety of different anglesbetween the main vessel 108 and the side-branch vessel 110. For example,in one embodiment, a particular prosthetic conduit 102 may be placed orused in vessels having anywhere from a 25-degree angle to a 45-degreeangle. Other embodiments may accommodate other angles and/or greater orlesser ranges of angles.

The prosthetic conduit system 100 according to various aspects of thepresent invention may be placed directly at a selected site.Alternatively, the prosthetic conduit system 100 may be introduced at afirst site and delivered to the desired location using a deliverysystem. The prosthetic conduit system 100 may also include a deploymentsystem for deploying the prosthetic conduit 102 at the selected site.The delivery system and/or the deployment system may be integrated intoor independent from the prosthetic conduit 102. The delivery systemsuitably places and stabilizes the prosthetic conduit 102 at a desiredlocation. The deployment system suitably configures and secures theprosthetic conduit 102 for operation following delivery.

The delivery system for positioning the prosthetic conduit 102 in thedesired position may comprise any suitable delivery system, such as, butnot limited to, one or more balloon catheters, guidewires, introducersheaths, guiding catheters, push tubes, and/or constraining sheaths.Referring to FIG. 4, an exemplary integrated delivery and deploymentsystem according to various aspects of the present invention comprises amain guidewire 408, a main balloon catheter 400, a side-branch guidewire410, and a side-branch balloon catheter 406. The main guidewire 408 andthe side-branch guidewire 410 may comprise any suitable guides tofacilitate navigation of the prosthetic conduit 102 to a desiredlocation and extension of the side-branch member 106. The guidewires408, 410 are advanced through the organism vessels to guide theprosthetic conduit 102 to the desired location.

The balloon catheters 400, 406 move the prosthetic conduit 102, securethe prosthetic conduit 102 in position, and/or deploy the prostheticconduit 102. The main balloon catheter 400 and side-branch ballooncatheter 406 may be conventional balloon catheters, and may possessvarying degrees of compliance. For example, in some embodiments theballoon catheters 400, 406 may be highly compliant, such as embolectomyballoon catheters, while in other embodiments the balloon catheters 400,406 may be non-compliant or semi-compliant high-pressure balloondilation catheters. Additionally, the balloon catheters 400, 406 may beeither over-the-wire or rapid-exchange balloon catheters.

The balloon catheters 400, 406 are configured to engage the guidewires408, 410 so that the balloon catheters 400, 406 may move along theguidewires. The balloon catheters 400, 406 are also configured to engagethe prosthetic conduit 102 to facilitate movement and deployment of theprosthetic conduit 102. For example, in the present embodiment, thedistal end 402 of the main member 104 may be releasably attached, by anysuitable mechanism, to the main balloon catheter 400, and the distal end306 of the side-branch member 106 may be releasably attached to theside-branch balloon catheter 406.

The prosthetic conduit 102 may be equipped with the delivery systemand/or deployment system prior to implantation. Alternatively, thedelivery system may be provided at the time of implantation. Forexample, the main balloon catheter 400 may be integrated into theprosthetic conduit 102 at the time of manufacture, or may be connectedto the prosthetic conduit 102 at the time of implantation. Similarly,the side-branch balloon catheter 406 may be omitted during the initialintroduction of the prosthetic conduit 102 into the vasculature. Therelatively small profile of the side-branch guidewire 410 may beadvantageous in certain situations compared to the side-branch ballooncatheter 406 or a tube. Thus, installation techniques and conduits maybe selected according to the particular configuration, application, orsituation.

Referring to FIG. 5, to place the prosthetic conduit 102 at a desiredlocation, the main guidewire 408 may be introduced into the vasculatureand navigated into the main vessel 108 (step 510). The main ballooncatheter 400, releasably attached to the distal end 402 of the mainmember, may be advanced along the main guidewire 408, advancing with itthe prosthetic conduit 102 (step 512). To enhance accuracy of placementof the prosthetic conduit 102, the side-branch guidewire 410 may be usedto align the side opening 204 of the main member 104 with the origin ofthe side-branch vessel 110 (step 514).

When the prosthetic conduit 102 is placed at a desired location, it maybe secured in the desired position (step 516), for example using theballoon catheters 400, 406. For example, referring to FIG. 6, uponproperly positioning the prosthetic conduit 102, the main member distalend 402 may be secured in position, for example by inflating the mainballoon catheter 400 while the side-branch member 106 remains retracted.The main member distal end 402 may be expanded by the main ballooncatheter 400 until the distal end 402 contacts the inner surface of mainvessel 108. Expansion of the main member distal end 402 tends tostabilize the prosthetic conduit 102 so that the side-branch member 106may be extended from the main member 104 and into the side-branch vessel110. The remainder of the main member 104 may also be fully expandedalong its entire length, either by one or more balloon catheters, byself-expansion, or by other suitable methods or apparatus.

After the position of the prosthetic conduit 102 has been secured, itmay be deployed for operation. Any suitable deployment system may beemployed to deploy the prosthetic conduit 102, and the deployment systemmay be configured in any suitable manner to configure the prostheticconduit 102 for operation. The prosthetic conduit 102 may be equippedwith the deployment system prior to implantation or at the time ofimplantation.

In the present embodiment, the prosthetic conduit 102 is configured sothat the side-branch member 106 is initially located within the mainmember 104 for delivery into a vessel. Such a configuration may easedelivery of the prosthetic conduit 102 into one or more vessels. Thus,the deployment system is suitably configured to extend the side-branchmember 106 from within the main member 104 and into the side-branchvessel 110, and expand the main member 104 and side-branch member 106 tofacilitate fluid flow. In particular, the deployment system includes themain guidewire 408, the side-branch guidewire 410, the main ballooncatheter 400, and the side-branch balloon catheter 406. When theprosthetic conduit 102 is properly positioned within the vasculature bythe delivery system, the side-branch balloon catheter 406 may be movedalong the side-branch guidewire 410 to the distal end 306 of side-branchmember 106, unless the side-branch balloon catheter 406 was placedsimultaneously with the prosthetic conduit 102. The side-branch member106 may be deployed by releasably attaching the side-branch ballooncatheter 406 to the side-branch member 106 to extend the side-branchmember 106 into the side-branch vessel 110. The side-branch member 106is then suitably extended along the side-branch guidewire 410 andsecured using the side-branch balloon catheter 406.

The side-branch balloon catheter 406 may be attached to the side-branchmember 106 in any suitable manner, such as by crimping side-branch stent112 and the surrounding graft material onto side-branch balloon catheter406 to releasably attach side-branch balloon catheter 406 to theside-branch member 106. In the present embodiment, the side-branchballoon catheter 406 may be positioned within the side-branch stent 112and inflated to a pressure high enough to engage the side-branch stent112, but low enough to avoid substantial expansion of the side-branchstent 112.

Referring to FIG. 7, after releasably attaching the distal end 306 ofthe side-branch member 106 to the side-branch balloon catheter 406, theside-branch balloon catheter 406 and the side-branch member 106 may beadvanced along the side-branch guidewire 410 to a desired location, thusextending the side-branch member 106 into the side-branch vessel 110(step 520). After extending the side-branch member 106, the side-branchstent 112 is in a position to be expanded to secure the side-branchmember 106 in position and facilitate flow. In an alternativeembodiment, the side-branch stent 112 may be installed separately, afterthe side-branch member 106 has been otherwise pushed or pulled frominside the main member 104.

Referring to FIG. 8, the side-branch stent 112 may then be expanded tocontact or adhere to the inner surface of the side-branch vessel 110(step 522). For example, the side-branch balloon catheter 406 isinflated to a selected pressure and for a selected duration, causing thedistal end of side-branch member 106 encompassing side-branch stent 112to circumferentially distend. The pressure is then suitably released andside-branch balloon catheter 406 may be moved toward the proximal end ofthe side-branch member 106. The side-branch balloon 406 is inflatedagain, causing the adjacent region of the side-branch member 106 todistend. This process of circumferential distention may be repeateduntil the side-branch balloon catheter 406 distends the entire length ofthe side-branch member 106 (step 524). When the main member 104 isplaced and fully dilated and the side-branch member 106 is fullyextended and distended, the prosthetic conduit 102 is fully deployed andoperational.

The balloon catheters 400, 406 facilitate delivery of the prostheticconduit 102 and extension of the side-branch member. Any suitablesystem, however, may be used to deliver and deploy the prostheticconduit 102 and side-branch member 106. For example, a snare may be usedto grasp the distal end 306 of side-branch member 106 and unfold it,either by pushing or pulling. Alternatively, referring to FIG. 9, thedeployment system may include a deployment tube 906, which may besimilar in outer diameter to the side-branch balloon 406 and positionedto provide a passageway into the distal end 306 of side-branch member106. The lumen of the deployment tube 906 may accommodate otherdeployment elements for deploying the prosthetic conduit 102, such asguidewires, balloon devices, snares, or other selected devices ormaterials. The deployment tube 906 may comprise, for example, a guidingcatheter and may have specific bends incorporated into its distal end tofacilitate the deployment of the side-branch member 106. Any suitableembodiment of a deployment tube may be utilized. During installation,once the side-branch balloon catheter 406 is inserted into the distalend 306 of side-branch member 106, the deployment tube 906 may beremoved or may be used as a support to stiffen and/or guide theside-branch balloon catheter 406, thus aiding in the deployment of theside-branch member 106. Thus, installation techniques and devices may beselected according to the particular configuration, application, orsituation.

Another embodiment of a delivery and deployment system according tovarious aspects of the present may be adapted to function with one ormore self-expanding stents. For example, referring to FIGS. 9 and 10,the delivery system may include a push tube 900 and a constrainingsheath 902 configured for maintaining the prosthetic conduit 102 in acompact configuration until delivery and deployment and delivering theprosthetic conduit 102 into the main vessel 108. Any suitable embodimentof a constraining sheath or structure to maintain the prosthetic conduit102 in a compact configuration may be utilized.

The prosthetic conduit 102 and push tube 900 may be positioned withinthe constraining sheath 902 such that the proximal end 412 of the mainmember 104 is in contact with the distal end of the push tube 900. Theconstraining sheath 902 suitably contains the prosthetic conduit 102 andthe push tube 900, and may be introduced into a vessel or other bodilyconduit, for example as a catheter may be introduced, and may beadvanced to a desired position within a vessel. When the prostheticconduit 102 is advanced to a desired location, the constraining sheath902 may be pulled back proximally, the push tube 900 may be pusheddistally, or both, to release the prosthetic conduit 102 from theconstraining sheath 902. Because the main member 104 may beself-expanding, once released from constraining sheath 902, the mainmember 104 may expand to contact the inner wall of main organism vessel108.

The constraining sheath 902 may suitably include an aperture forallowing the side-branch guidewire 410 to protrude through theconstraining sheath 902, which allows the side-branch guidewire 410 tohelp align the side opening 204 with the origin of the side-branchvessel 110. The side-branch guidewire 410 may be extended laterally fromthe constraining sheath 902 and into the side-branch vessel 110 tofacilitate the correct positioning of the prosthetic conduit 102. Whenthe prosthetic conduit 102 is correctly positioned, the side-branchguidewire 410 may be retracted, allowing the constraining sheath 902 tobe moved axially with respect to the prosthetic conduit 102.

The constraining sheath 902 may be configured to the particularapplication and environment. For example, referring to FIGS. 11 and 12,the constraining sheath 902 may include a distal tip 904, configured toenhance navigability of the constraining sheath 902 within bodilyconduits. The distal tip 904 may be configured to have a tapered profilethat reduces resistance during movement within bodily conduits and maysuitably include multiple wedge-shaped segments 1100. The taperedprofile and wedge-shaped segments 1100 may enhance navigability withinbodily conduits by providing a more hydro-dynamic distal tip 904 for theconstraining sheath 902. The distal tip 904 may also be configured as asubstantially closed structure to inhibit bodily fluids from enteringthe constraining sheath 902. Furthermore, the wedge-shaped segments 1100may be configured to be flexible, allowing the constraining sheath 902to be easily moved relative to the prosthetic conduit 102.

The push tube may be configured in any suitable manner to facilitatedelivery of the prosthetic conduit 102. For example, referring to FIG.13, an exemplary embodiment of a push tube 900 configured to deliver theprosthetic conduit 102 with the self-expanding main member 104 within anorganism vessel may include a cross-section shaped as an incompleteannulus with a gap 1300. The push tube 900 with the gap 1300 may beconfigured to enable the push tube 900 to be easily removed from theorganism vessel after deployment of the prosthetic conduit 102 withoutremoving or otherwise disturbing the side-branch balloon catheter 406 orthe side-branch guidewire 410.

The push tube 900 may also include a section that extends within thelumen of the main member 104, providing additional stiffness duringinstallation. The push tube 900 may also include a section extendingalong the entire length of the main member 104, and abutting the distalend 402 of the main member 104, which tends to offer further controlduring installation of the prosthetic conduit 102.

The side-branch member 106 may be pushed or pulled out of the interiorof the main member 104 in any suitable manner, for example by pushing itout with the releasably attachable side-branch balloon catheter 406.Thus, in this embodiment, the main member 104 is self-expanding whilethe side-branch member 106 is balloon expandable. Any suitabledeployment system, however, may be used to extend the side-branch member106 from within the main member 104.

The prosthetic conduit 102 according to various aspects of the presentinvention may be manufactured from many different materials orcombinations of materials and may be constructed by any suitable method.A prosthetic conduit 102 according to various aspects of the presentinvention, however, is formed using material that may becircumferentially distended with minimal foreshortening and recoil.Accordingly, the material(s) for the prosthetic conduit 102 may betreated to facilitate such distention characteristics.

For example, referring to FIG. 14A-B, the main member 104 may beconstructed by initially forming a film-tube (step 1410) of a thin,flexible material, such as a microporous polyethylene film, for examplea segment of Solupor® 7P03A microporous polyethylene film manufacturedby DSM Solutech. In the present embodiment, the film has a nominalthickness of about 50μ, a nominal porosity of about 85%, and a nominalweight per surface area of 7 g/m2, though any of these characteristicsmay vary according to the particular application. Various alternativefilm-tubes may be employed. For example, films of any suitable material,both porous and non-porous may be used. The diameter and wall thicknessof the graft component of main member 104 may be constant or may vary tocreate graft components with different properties and differentgeometries, such as but not limited to tapers and the like.

To form the main film-tube, the film is cut to a selected size, such asan approximately 230×155 mm rectangular piece, and wrapped around thecircumference of a mandrel, suitably comprising stainless steel, andhaving a desired diameter, such as about 16 mm, to form a film-tube.Various tooling (mandrels, rods, etc) may be used. The tooling ontowhich the film is applied may be of a constant outer diameter, or mayhave a variable outer diameter to create tubes of various geometriessuch as tapers and the like. Any suitable tooling having any suitableshape may be employed.

In the present embodiment, the tube is wrapped in a directionperpendicular to the major axis of the tube. The film may be wrapped inany suitable manner, for example, helically with respect to the majoraxis of the tube, or in any other appropriate manner. The wrapping iscompleted with the 230 mm long edges of the rectangular piece parallelto the major axis of the mandrel such that a desired thickness isachieved. In the present embodiment, approximately three layers of thefilm cover the mandrel. The circumference of the 16 mm mandrel isapproximately 50.3 mm, so to achieve a film thickness of approximatelythree layers after wrapping, one side of the rectangular piece is cut toa dimension of about 155 mm, providing a selected overlap length, suchas approximately 4 mm. During wrapping, the film may be treated, such aswet with isopropyl alcohol, to enable the film to better lay smoothly.

With the wrapping complete, both ends of the wrapped film section aresecured to the mandrel, such as with wire. Next, the polyethylene filmmay be secured along its length to the mandrel. For example, thepolyethylene section may be helically wrapped with porouspolytetrafluoroethylene film, suitably covering the film-tube entirely,ensuring that the layers of the polyethylene film contact each other.

The layers of the wrapped film are bonded together to form a single tube(step 1412). Bonding of the layers may be achieved by any suitablemethod. For example, the 16 mm mandrel may be placed in an airconvection oven set at 150° C. for 10 minutes and subsequently removedand allowed to cool. Once cool, the helically wrapped porous PTFE filmas well as the securing wire are removed and discarded. The resulting 16mm inner diameter polyethylene tube is then removed from the 16 mm outerdiameter mandrel. The 150° C. temperature and 10 minute time combinationis chosen to bond the film layers to each other, forming a robust tube,but leaving the porous nature of the polyethylene film substantiallyunchanged, and avoiding thermal degradation of the film. Any suitabletemperature and time combination, however, may be used. Alternatively,heated dies that contact the film either partially or wholly may also beused. Further, various adhesives or coatings may be applied to the filmto effect bonding. The use of such adhesives or coatings may result intubes that are composite in nature, having the combined characteristicsof the adhesive or coating as well as the characteristics of the filmmaterial.

In the present embodiment, the main member 104 is a polyethylenefilm-tube without any stent. Alternative embodiments of main member 104may include stents of any suitable number, form, and material and maymake use of various methods of attaching or incorporating the stents tothe main graft 202.

In an alternative embodiment of main member 104, for example, alamination process may be used to secure main graft 202 to main stent200. In this exemplary embodiment the main graft 202 is made fromSolupor® 8P07A microporous polyethylene film manufactured by DSMSolutech. The film has a nominal thickness of about 50μ, a nominalporosity of about 85%, and a nominal weight per surface area of 8 g/m2,though any of these characteristics may vary according to the particularapplication.

To form the main member 104, two rectangular pieces of the polyethylenefilm and a self-expanding stent are utilized. The two film pieces haverespective dimensions of approximately 32×66 mm and 32×69 mm. A 9.25 mmstainless steel mandrel may serve as the form about which the pieces offilm may be wrapped. Prior to applying the polyethylene film onto themandrel, the mandrel is wrapped helically with porous PTFE film. Thehelical wrapping is done so as to create a uniform surface onto whichthe polyethylene film may be applied. This helical wrap serves as anunderlayer over which the main member 104 is constructed. The 32×66 mmrectangular section of polyethylene film is next wrapped over the PTFEwrapped 9.25 mm mandrel. The wrapping is completed with the 32 mm longedges of the film section parallel to the major axis of the mandrel. Aspreviously mentioned, during wrapping the polyethylene film may betreated, such as wet with isopropyl alcohol, enabling the film to laymore smoothly and form about the circumference of the PTFE wrappedmandrel more easily.

With the 32×66 mm section of polyethylene film wrapped about the PTFEwrapped mandrel, the self-expanding stent is carefully slid coaxiallyover the polyethylene film section. The self-expanding stent has anominal inner diameter of 10 mm and a length of approximately 42 mm. Thestent is centered along its length with respect to the section of thepolyethylene film. This results in the stent extending approximately 5mm beyond either edge of the polyethylene film section. Theself-expanding stent utilized in this alternative embodiment of the mainmember 104 consists of 9 connected “Z” rings, with the outermost ring ateach end flared to a larger diameter. The 5 mm lengths of stentextending beyond the edges of the polyethylene film section correspondto the two flared outermost “Z” rings.

With the self-expanding stent carefully positioned over the 32×66 mmrectangular polyethylene film section, porous PTFE film is used to wrapthe flared outermost “Z” rings of the stent and bring them into contactwith the PTFE film wrapped mandrel. The 32×69 mm rectangular filmsection is next wrapped over the self-expanding stent. The wrapping iscompleted with the 32 mm long edges of the film section parallel to themajor axis of the mandrel and aligned with the polyethylene film sectionunderneath the self-expanding stent. Again, during wrapping thepolyethylene film may be treated, such as wet with isopropyl alcohol, toenable the film to lay more smoothly and form about the circumference ofthe self-expanding stent more easily.

Next, the entire assembly of the 32×69 mm section of polyethylene film,the self-expanding stent and the 32×66 mm section of polyethylene filmmay be secured along its length to the porous PTFE wrapped mandrel. Forexample, the entire assembly may be helically wrapped with porouspolytetrafluoroethylene film, ensuring that the layers of thepolyethylene film and the self-expanding stent suitably contact eachother.

The layers of the assembly are bonded together to form the alternativeembodiment of the main member 104. Bonding of the layers may be achievedby any suitable method. For example, the 9.25 mm mandrel may be placedin an air convection oven set at 140° C. for 10 minutes and subsequentlyremoved and allowed to cool. Once cool, the helically wrapped porousPTFE film on the outside of the assembly as well as the PTFE filmconstraining the outermost “Z” rings of the self-expanding stent isremoved and discarded. Next, the porous PTFE film wrapped about thecircumference of the 9.25 mm mandrel is removed by carefully pulling onthe free end of the film and causing it to unwrap underneath thealternative embodiment of the main member 104. The resulting main member104 is then removed from the 9.25 mm outer diameter mandrel.

In yet another alternative embodiment of the main member 104, a textilecomponent may be combined with the polyethylene film by way oflamination. As in the preceding embodiment, for example, Solupor® 8P07Amicroporous polyethylene film manufactured by DSM Solutech may beutilized. The main characteristics of the 8P07A film are describedabove. Although the 8P07A film is chosen for this particular exemplaryembodiment, any suitable film or membrane made of any suitable materialwith any number of suitable characteristics may be used.

The textile component is a tubular braid made from polyethyleneterephthalate (PET) fibers. The braid is made from a total of 36 strandsof multifilament PET yarn and is manufactured by Secant Medical,Perkasie, Pa. Eighteen of the 36 strands are 44 denier, while theremaining eighteen are 20 denier. The tubular braid has an innerdiameter of about 5 mm and a braid angle of about 100 degrees. Althoughthis particular tubular braid is chosen for this embodiment, anysuitable tubular braid of any suitable material may be employed.Additionally, the textile component need not be tubular. The textilecomponent may come in any form, for example, in the form of a sheet orotherwise flat material and may be suitably applied to create anydesired geometry. Furthermore, the textile component need not bebraided. The textile component may be manufactured by any number ofmeans such as but not limited to weaving or knitting. In certainembodiments the textile component may comprise individual strands offibers arranged in any suitable pattern.

To form the main member 104, two rectangular pieces of the polyethylenefilm and a 55 mm long length of the PET braid are used. The two filmpieces have respective dimensions of approximately 35×60 mm and 38×60mm. A 4.1 mm stainless steel mandrel may serve as the form about whichthe main member 104 may be constructed. As described in the previousembodiment, prior to applying the polyethylene film onto the mandrel,the mandrel is wrapped helically with porous PTFE film. The helicalwrapping is done so as to create a uniform surface onto which thepolyethylene film may be applied. This helical wrap serves as anunderlayer over which the alternative embodiment of the main member 104is constructed. The 35×60 mm rectangular section of polyethylene film isnext wrapped over the PTFE wrapped 4.1 mm mandrel. The wrapping iscompleted with the 60 mm long edges of the film section parallel to themajor axis of the mandrel. As previously mentioned, during wrapping, thepolyethylene film may be treated, such as wet with isopropyl alcohol,enabling the film to lay more smoothly and form about the circumferenceof the PTFE wrapped mandrel more easily. Any suitable treatment may beused to facilitate the wrapping.

With the 35×60 mm section of polyethylene film wrapped about the PTFEwrapped mandrel, the PET braid is carefully slid coaxially over thepolyethylene film section. The braid is positioned such that it coversapproximately half of the length of the polyethylene film section.

With the PET braid carefully positioned over half of the 35×60 mmrectangular polyethylene film section, the 38×60 mm rectangular filmsection is next wrapped over the 35×60 mm film section and the overlyingbraid. The wrapping is completed with the 60 mm long edges of the filmsection parallel to the major axis of the mandrel and aligned over the35×60 mm polyethylene film section. Again, during wrapping, thepolyethylene film may be treated, such as wet with isopropyl alcohol, toenable the film to lay more smoothly and form about the circumference ofthe 35×60 mm film section and the overlying braid more easily.

Next, the entire assembly of the 35×60 mm section of polyethylene film,the PET braid and the 38×60 mm section of polyethylene film may besecured along its length to the porous PTFE wrapped mandrel. Forexample, the entire assembly may be helically wrapped with porouspolytetrafluoroethylene film, ensuring that the layers of thepolyethylene film and the self-expanding stent suitably contact eachother.

The layers of the assembly are bonded together to form the alternativeembodiment of the main member 104. Bonding of the layers may be achievedby any suitable method. For example, the 4.1 mm mandrel may be placed inan air convection oven set at 140° C. for 10 minutes and subsequentlyremoved and allowed to cool. Once cool, the helically wrapped porousPTFE film on the outside of the assembly is removed and discarded. Next,the porous PTFE film wrapped about the circumference of the 4.1 mmmandrel is removed by carefully pulling on the free end of the film andcausing it to unwrap underneath the alternative embodiment of the mainmember 104. The resulting main member 104 is then carefully removed fromthe 4.1 mm outer diameter mandrel.

For both of the alternative embodiments of the main member 104 above,the 140° C. and 10 minute temperature and time combination is chosen tobond the various material layers to each other, forming a robuststructure, but leaving the porous nature of the polyethylene filmsubstantially unchanged, and avoiding thermal degradation of the filmand the other materials utilized. Any suitable temperature and timecombination, however, may be used.

Additionally, for both of the alternative embodiments of the main member104 above, the mandrel over which the embodiment is constructed iswrapped helically with porous PTFE tape. The PTFE tape facilitates theremoval of the finished main member 104 embodiment from the mandrelwithout significant distortion or damage. This is of particular concernfor embodiments which include delicate stent and/or textile componentsor components of a generally fragile nature. Any suitable method may beemployed to ease the removal of the finished main member 104 from itstooling. Various tapes or substrates of any suitable material may beapplied in any suitable fashion to the surface of the tooling. Thesurface of the tooling may be treated with various coatings. The toolingitself may be collapsible or deformable by various means.

The two exemplary embodiments described above illustrate how variouscombinations of graft materials and stents may be combined to createdifferent embodiments of the main member 104 with differentcharacteristics. The process of laminating various materials and/orcomponents to form the main member 104 and more generally, grafts and/orstent-grafts, affords a relatively simple and effective means ofmanufacturing complex devices. The lamination technique may obviate manytedious and costly manufacturing methods, for example, the use ofsutures or thread to attach stent components onto grafts.

Returning now to the present exemplary embodiment of the main member104, the 16 mm film-tube may then be cut, if desired, to a particularlength, such as approximately 70 mm. The side opening 204 may then beformed in the tube, such as by using a 4 mm diameter biopsy punch (step1414). Any suitable geometry and tooling may be employed to create theside opening 204. Additionally, alternative embodiments of the sideopening 204 may include sections of material protruding laterally fromthe main member 104, to which the side-branch member 106 may beattached. It should be noted that although the exemplary embodiments ofmain member 104 are not processed to provide characteristics such asenhanced flexibility, kink resistance and limited foreshortening, suchprocessing may be included using the methods described herein or by anyother suitable means.

The side-branch member 106, such as an approximately 4 mm inner diameterpolyethylene film-tube, may be formed in the same manner as theapproximately 16 mm inner diameter polyethylene film-tube describedabove (step 1416). In particular, a graft material, such as 7P03Amicroporous polyethylene film, is cut to a selected size and shape, suchas an approximately 230×42 mm rectangle, and wrapped around thecircumference of a mandrel having the desired outer diameter, such asabout 4 mm. In this instance, the circumference of the 4 mm mandrel isapproximately 12.6 mm, so to achieve a film thickness of three layersafter wrapping, one side of the rectangular piece is cut to a dimensionof 42 mm, providing approximately 4 mm extra film length for overlap.During wrapping, the film may be wet with isopropyl alcohol tofacilitate smooth layers.

With the wrapping complete, both ends of the 230 mm long wrapped filmsection may be secured to the mandrel, for example with wire. Next, thefilm is secured in position, such as by helically wrapping a porous PTFEfilm over the 230 mm long wrapped film section, covering the sectionsubstantially entirely. The PTFE film tends to secure the polyethylenefilm about the mandrel so that the layers of the polyethylene filmcontact each other.

The layers of the side-branch tube are then suitably bonded together toform the side-branch tube (step 1418). For example, the 4 mm mandrel maybe placed in an air convection oven set at 150° C. for 5 minutes andsubsequently removed and allowed to cool. Once cool, the helicallywrapped porous polytetrafluoroethylene film as well as the securing wireare suitably removed and discarded. The temperature and duration may beselected according to any suitable criteria to bond the film layers toeach other and form a robust tube, but substantially maintaining theporous nature of the polyethylene film and avoiding any significantthermal degradation or weakening of the film. The resulting 4 mm innerdiameter polyethylene tube is then removed from the 4 mm outer diametermandrel and suitably cut to a desired size, such as into two equallengths.

In accordance with various aspects of the present invention, theside-branch tube and/or the main member 104 may be treated in anysuitable manner to provide selected characteristics, such ascircumferential distention and/or extension capabilities. In the presentembodiment, the side-branch tube is treated to facilitate distention ofat least a portion of the side-branch tube with relatively lowforeshortening and/or recoil. The side-branch tube is also treated tofacilitate kink resistance.

For example, the side-branch tube may be processed with cycles of heat,stretching, and/or compressing. The side-branch tube may be heated andstretched to a desired length and/or diameter. In the presentembodiment, the side-branch tube may be initially marked at a knowninterval (step 1420), such as two marks at a 70 mm interval centeredalong the length of the side-branch tube. The film-tube is then securedto a mechanism configured to stretch the side-branch tube. Any suitablestretching apparatus may be used, and may include any suitable mechanismfor securing the tube, stretching the tube, heating the tube, measuring,and/or controlling the amount and rate of stretching. For example, asliding mandrel mechanism may comprise two lengths of 3 mm outerdiameter stainless steel tubing and a length of 1.6 mm outer diameterstainless steel rod. One end of the rod is bent and inserted into one ofthe 3 mm outer diameter tubing lengths such that it is substantiallyimmobile. Both lengths of the 3 mm outer diameter tubing have a 360°groove cut into the wall approximately 3 mm away from one end. Thefilm-tube is fitted coaxially over the 1.6 mm rod and attached to the 3mm outer diameter tubing by manually tying a wire over the film-tube andinto the groove at the end of the 3 mm outer diameter tubing. The otherlength of 3 mm outer diameter tubing is then fitted coaxially over the1.6 mm rod and the same manual wire tying process is used to secure theother end of the film-tube to the 3 mm outer diameter tubing.

When the side-branch tube is secured to the sliding mandrel mechanism,the assembly is exposed to heat (step 1422), such as via an airconvection oven set at a selected temperature, such as 150° C. The ovenis configured with holes at each end so that the sliding mandrelmechanism and the attached film-tube can be inserted such that thefilm-tube is approximately centered within the oven chamber and each ofthe 3 mm outer diameter tubing lengths extend out of each end of theoven. The side-branch tube is heated for a selected duration, such asone minute, and then slowly stretched by manually pulling the ends ofthe 3 mm outer diameter tubing lengths extending out of each end of theoven (step 1424). The film-tube is stretched in this manner to a desiredlength and/or diameter. Other parameters, such as the tensile forceexperienced by the tube, or the outer diameter of the tube duringstretching may also be monitored and/or controlled.

In the present embodiment, the side-branch tube is stretched until themarks are approximately 130 mm apart. The lengthening causes thefilm-tube to reduce in diameter such that it substantially contacts the1.6 mm rod. Tension is maintained on the film-tube, now stretched andreduced in diameter, ensuring that no significant change in lengthoccurs while the sliding mandrel mechanism is removed from the oven. Thefilm-tube is next allowed to cool and subsequently removed from thesliding mandrel mechanism.

At this point, the side-branch tube may be circumferentially distended.The side-branch tube may be further processed, however, to achieveadditional characteristics. For example, the side-branch tube may bedistended to facilitate later distention with reduced force up to aselected limit. For example, the side-branch tube may be initiallydistended to a first selected diameter (step 1426), such as by manuallyfitting the tube over a tapered stainless steel mandrel having a 2 mmouter diameter section approximately 200 mm in length, and tapering upto an outer diameter of 3.8 mm over a length of approximately 40 mm.When fitted entirely over the 3.8 mm outer diameter section of themandrel and pulled taut, a distance of approximately 81 mm separates thetwo pen marks on the film-tube. Next, the tube is removed from the 3.8mm tapered mandrel, and then further distended over a 4 mm taperedmandrel (step 1428). When fitted entirely over the 4 mm outer diametersection of the mandrel and pulled taut, a distance of approximately 75mm separates the two pen marks on the film-tube. In the presentembodiment, the distention is completed in two steps to make the processeasier, though the distention may be performed in greater or fewersteps.

Varying amounts of distention may be performed to achieve varying finaldistensibility characteristics. The film-tube may be distended anywherefrom zero to near the circumference at which it breaks, and thedistention may be accomplished in any number of steps. The distention ofthe exemplary film-tube is suitably performed at ambient temperatureconditions. Various temperature conditions, however, may be employedduring the distention. The use of elevated temperature may be requiredfor film-tubes of different materials, or for film-tubes of greaterthickness. Moreover, any suitable mechanism and method may be employedto complete the distention. For example, as an alternative to the use oftapered mandrels, a balloon or bladder may be utilized to pressurize thefilm-tube and cause distention.

The side-branch tube may be further processed, such as to add featureslike flexibility and/or kink resistance. In the present embodiment, theside-branch tube is processed for kink resistance by sequentiallystretching the tube to achieve a desired diameter and compressing theside-branch tube to form small corrugations. The corrugations may beformed in any suitable manner, and facilitate bending of the side-branchmember 106 without kinks.

For example, the side-branch tube may be initially stretched (step 1430)using any suitable mechanism, such as a linear slide with a manuallydriven lead screw. Each end of the side-branch tube is secured onto thelinear slide mechanism, for example using clamps. Heated air, such asfrom a hair drying gun set on low, may be applied to warm theside-branch tube and soften the graft material. Turning a hand crankconnected to a lead screw actuates the linear slide. The film-tube maythus be slowly stretched. Periodically, the stretching of the film-tubemay be halted, allowing the stress within the tube to diminish, therebyavoiding breaking of the tube. The film-tube is stretched until adesired distance, such as approximately 144 mm, separates the two markson the side-branch tube. The film-tube may also be stretched until adesired diameter is achieved. The side-branch tube may then be allowedto cool and/or relieve stress for a selected time and temperature, suchas at least five minutes at ambient temperature. The tube is thenremoved from the linear slide mechanism. The processes of distending thetube and subsequently stretching it to reduce its diameter may berepeated any number of times if desired.

The side-branch tube may also be processed to provide othercharacteristics, such as resistance to kinking and/or foreshortening.For example, to add kink resistance and reduce foreshortening upondistention, the side-branch tube may be processed to form corrugations.For example, the side-branch tube may be fitted coaxially over a 1.2 mmdiameter stainless steel rod and again marked for reference (step 1432).The marks are separated by a selected interval, such as 50 mm, and themarks may be centered along the length of the side-branch tube. Theside-branch tube is also suitably constrained against the rod, forexample using a thin, strong, porous PTFE film helically wrapped overthe side-branch tube.

The overwrapped side-branch tube on the 1.2 mm diameter rod may then becompressed. To facilitate compression, the side-branch tube is suitablyheated (step 1434), such as in an air convection oven set at a selectedtemperature and duration, such as 70° C. for at least about 10 minutes.The side-branch tube may then be removed from the oven and compressedlongitudinally (step 1436), tending to cause a reduction in length. ThePTFE film overwrap tends to inhibit formation of gross corrugationsalong the surface of the film-tube during compression. Any suitablemethod may be used to control the size of the corrugations formed alongthe surface of the film-tube. For example, the film-tube while on the1.2 mm diameter rod may be placed within a tube having an inner diameterslightly larger than the outer diameter of the film-tube prior to beingoverwrapped, and may then be longitudinally compressed within the tube.

The film-tube is longitudinally compressed a desired amount, for exampleso that a distance of approximately 28.5 mm separates the two pen marksoriginally separated by a distance of 50 mm. The side-branch tube maythen cool to ambient temperature, the polytetrafluoroethylene filmoverwrap is removed, and the film-tube is removed from the 1.2 mmdiameter rod. The resulting 1.2 mm inner diameter polyethylene film-tubemay then be gently pulled (step 1438) or otherwise smoothed to removeany inconsistently to large corrugations, leaving a substantiallyuniform tube surface.

The longitudinal compression tends to impart corrugations along thesurface of the film-tube or otherwise shorten the film-tube. In somematerials, like polyethylene, the compression may cause the tube surfaceto exhibit small corrugations or wrinkles. For other materials, thecompression may cause compression of the material itself, such that thematerial condenses without forming corrugations in the surface. Theporosity of the material and the temperature may also affect theformation of corrugations or other shortening of the film-tube. Thewrinkles or other compression serve to enhance the flexibility of thetube, tending to allow the tube to undergo substantial bending withoutkinking, and also serve to inhibit any change in length of the film-tubeduring distention. The processes for achieving the variouscharacteristics, including kink resistance and minimized foreshortening,may be applied to other materials as well, such as material treated inaccordance with the disclosure of U.S. Pat. No. 5,800,522, issued Sep.1, 1998, to Campbell, et al. Moreover, other methods may be applied toform corrugations or compress the tube, such as tying thin wires spacedat regular intervals around the circumference of the film-tube while thetube is on the 1.2 mm diameter rod. With the wires in place, the tubemay be longitudinally compressed. The presence of the wires during thecompression results in the formation of wrinkles of a pre-determinedsize.

Any number of methods may be used to enhance flexibility, kinkresistance and foreshortening. The methods may be chosen to suitparticular embodiments of graft components, main members and side-branchmembers incorporating various combinations of graft materials andstents. Grafts incorporating certain combinations of materials orcertain combinations of stents and grafts may not easily be compressedlongitudinally as described above. In such instances, other forms ofmanipulation may be employed to impart improved flexibility. Forexample, enhanced flexibility may be achieved by radial compression suchas by rolling between plates, rolling manually, and/or usage of radialcompression devices such as those manufactured by Machine Solutions,Inc. located in Flagstaff, Ariz. For certain embodiments gentle bendingmay be an effective method of increasing flexibility.

Although the graft component 310 described above is circumferentiallydistensible with low recoil and foreshortening, the use ofnon-distensible tubes as the graft component is possible. The graftcomponent, distensible or not, may be of any suitable material known inthe prior art, or any suitable material that may become available in thefuture. Additionally, graft component 310, may be constructed from anysuitable form or combination of forms such as but not limited toextruded tubing, braided tubing, textile tubing, and as discussed tubingcreated from films or membranes. The graft component may be processed byany suitable methods. The wall thickness of the graft component 310 ofthe side-branch member 106 may be constant or may vary to create graftcomponents with different properties. For example a graft component mayhave a thinner wall at the distal end, and a thicker wall at theproximal end, or vice versa. The graft component may further have anysuitable degree of porosity. Further, all of the techniques andmaterials may be applied to other components of the prosthetic conduit102, such as the main member 104, or other devices and materials.

In an alternative embodiment, a graft component may be created from awoven textile tube. Woven textile tubes, such as braided tubes formedgenerally of helically wound strands, may be constructed from varioussuitable materials, such as but not limited to polyester, polypropylene,and polytetrafluoroethylene. Braided tubes may exhibit distensiblebehavior. Typically, distention of braided tubes is accompanied bypronounced foreshortening. The relationship between the amount ofdistention and the amount of foreshortening can be varied according tothe parameters utilized in the manufacture of the tube.

A braided tube according to various aspects of the present invention iscircumferentially distensible. A braided tube may be initially elongatedin the direction of the major axis until the ensuing reduction indiameter is complete. Next, the tube may be cut to a selected length andfitted coaxially over a rod or mandrel of appropriate outer diameter.The ends of the tube are then secured to the rod or mandrel using wire,and the elongated braided tube is then overwrapped with porouspolytetrafluoroethylene film and longitudinally compressed. The tube,prior to or during the longitudinal compression, may be heated.

The porous polytetrafluoroethylene film tends to control the size ofcorrugations along the surface of the tube. Next, for example, the tubeis suitably placed in an oven and heated. The time and temperatureparameters are suitably chosen such that the tube, after removal fromthe mandrel, substantially maintains the longitudinally compressedlength, but the strands that form the tube are not permanently bonded toeach other. In this fashion, the tube may be distended, but having beenlongitudinally compressed, foreshortens minimally. The braided tube maybe gently pulled to remove any inconsistently large corrugations thatmay have been formed during the longitudinal compression process.

Any suitable degree of longitudinal compression may be performed to thebraided tube. For example, in one embodiment two marks separated by aknown distance may be placed on the braided tube prior to the tube beingelongated, and the marks may be returned to their original spacingduring the longitudinal compression process. Any suitable method may beemployed to maintain the tube in its longitudinally compressed state butstill allow distention. For example, a mild adhesive may be applied tothe surface of the tube either partially or wholly. Alternatively,heated dies that contact the surface of the tube either partially orwholly may be used.

In accordance with various aspects of the present invention, theside-branch tube may be equipped with a support (step 1440), such as theside-branch stent 112 at the distal end of the side-branch member 106.The stent may be added to the side-branch tube in any appropriatemanner. For example, one end of the 1.2 mm inner diameter polyethylenegraft component may be slightly flared, such as by using a pair of smallhemostats. The graft component may then be fitted coaxially onto a 1.2mm diameter stainless steel rod and constrained against the rod, forexample using a helical overwrap of thin, strong, porous PTFE film. Theoverwrapping suitably begins on the rod adjacent to the non-flared endof the graft component and ends at the base of the small flare at theend of the graft. The flared end of the graft may then be everted, forexample manually using small hemostats. The PTFE overwrap film may beremoved as necessary as the graft is everted until an everted section ofa desired length, such as approximately 22 mm long, is obtained.

The stent may then be placed within the folded over portion of thegraft. For example, a 0.64 mm diameter wire is suitably pushedunderneath the everted section of the graft component, slightlydistending the everted section, creating a small annular space betweenthe everted section and the underlying graft component. A selectedstent, such as an 18 mm long balloon-expandable side-branch stent 112,is then placed within the annular space between the everted section andthe underlying graft component, the end of the side-branch stent 112abutting the fold at the end of the everted section of the graftcomponent.

The approximately 4 mm long length of everted graft component extendingbeyond the stent is then suitably bonded to the underlying graftcomponent, for example using a conventional soldering iron, to maintainthe position of the side-branch stent 112. The bonding process suitablycontrols the application of heat to ensure that the graft component isnot overly heated, substantially changing the graft properties, ordamaged during the bonding process. At this point, the everted sectionof graft component over the side-branch stent 112 may be radiallycompressed, reducing the outer diameter of the end of the graftcomponent encompassing the stent. The remaining PTFE overwrap film maybe removed and the graft component and stent are suitably removed fromthe 1.2 mm diameter rod.

Alternative embodiments of the side-branch tube may omit the side-branchstent 112 or replace it, for example with another type of stent. Forexample, the side-branch stent 112 may be a self-expanding stent. Asuitable self-expanding stent may be placed within the annular spacecreated between the everted section and the underlying film-tube asdescribed. In such an embodiment the self-expanding stent may bemaintained in a compact configuration by the graft component coveringit, and thus the combination of the self-expanding stent and the graftcomponent is functionally balloon expandable. One or more stents may beused at any location along the graft component. In some embodiments theuse of both balloon expandable and self-expanding stents may bepreferred. Further, any suitable method may be employed to attach orincorporate stents to the graft component. For example stents maysutured to the graft component, or may be attached by an adhesive. Insome embodiments it may be possible to bond the stent to the graftcomponent using heat.

In an exemplary embodiment according to various aspects of the presentinvention, an attachment area for attaching the main member 104 to theside-branch member 106 is provided (step 1442). For example, theside-branch member 106 suitably includes the conical section 302 and/orthe flange 304. The conical section 302 may be formed in or attached tothe side-branch member 106 in any suitable manner. For example, theportion of the graft component from the bond site 404 to the proximalend 308 is initially distended by coaxially fitting it over a 2 mmdiameter steel rod, suitably such that the graft component does notcompress longitudinally and become grossly corrugated, or substantiallyelongate. Once distended, the graft component and incorporated stent aresuitably removed from the 2 mm diameter rod. In the present embodiment,the length of the graft component from the bond site 404 to the proximalend 308 is approximately 50 mm.

To form the conical section 302 and flange 304, the graft component,starting at the proximal end 308, is distended in a conicalconfiguration, such as by fitting it over a 4 mm tapered mandrel. Thetapered mandrel increases from an outer diameter of approximately 1.3 mmto an outer diameter of 4 mm over a length of approximately 30 mm. Inthe present embodiment, the graft component is fitted over the 4 mmtapered mandrel such that the proximal end extends approximately 6 mmonto the 4 mm outer diameter section of the mandrel.

Thus, in this particular embodiment, distending the proximal end 308over a tapered or conically shaped mandrel at ambient temperature formsthe conical section 302 of the side-branch member. The conical sectionmay have any suitable geometry, provided that the proximal end of theside-branch member is able to be attached to the side opening 204 of themain member 104. Additionally, the conical section may be formed by anysuitable method at any suitable temperature, such as for exampledistention via a balloon, or the use of any other tube flaringequipment. The method and temperature employed are dependent on theembodiment of the graft component. In an alternative embodiment, theconical section may be a separate piece, attached to the side-branchmember by any suitable method.

Similarly, the flange may be formed in or attached to the side-branchmember 106 in any suitable manner. For example, while side-branch member106 remains situated on the 4 mm tapered mandrel, four cuts may be madeat the proximal end of the graft component, for example using a razorblade. The cuts are suitably substantially parallel to the major axis ofthe graft component, extending approximately 3 mm from the proximal endof the graft component at selected intervals, such as 0, 90, 180, and270° around the circumference of the proximal end 308 of the graftcomponent. The four 3 mm long cuts form four substantially equalsections around the circumference of the proximal end 308 of the graftcomponent. The four sections may then be bent to a position extendinglaterally, perpendicular to the major axis of the graft component, toform the flange 304. With the embodiment of the conical section 302formed via the 4 mm tapered mandrel, and the embodiment of the flangecreated by the four equal sections around the circumference of theproximal end of the graft component, the graft component may then beremoved from the 4 mm tapered mandrel.

The flange 304 may be of any suitable geometry to facilitate and/orstrengthen the connection of the side-branch member to the main member.The flange 304 may be formed by any suitable mechanism, such as, but notlimited to, flaring the proximal end 308 of the side-branch member 106and then everting the flared section, or using any other suitable tubeflanging equipment or process. Alternatively, the flange 304 may be aseparate piece, attached to the side-branch member 106 by any suitablemethod, or attached to the side opening 204, or formed from the materialsurrounding the side opening 204. Any adaptation of the proximal end 308of the side-branch member 106, or the side opening 204 in the mainmember 104, either alone or in combination, may be utilized.

The main member 104 and side-branch member 106 may be connectedaccording to any suitable technique or process (step 1444). In thepresent embodiment, for example, the main member 104 is partially fittedcoaxially onto a 16 mm outer diameter mandrel, leaving the lumen of themain member 104 and the side opening 204 accessible. The side-branchmember 106 may be inserted, distal end first, into the lumen of the mainmember 104 and through the side opening 204 until the flange 304 abutsthe inner surface of side opening 204.

When the flange 304 abuts the inner surface of the main member at theside opening 204, the flange 304 may be secured to the main member 104in any suitable manner. For example, the main member 104 may be advanceddown the length of the 16 mm outer diameter mandrel, trapping the fourequal sections comprising the flange 304 between the mandrel and themain member 104. The main member 104 and the side-branch member 106, viaflange 304, are then bonded together, for example thermally, at the sideopening 204, such as via a soldering iron. The bonding, however, may beperformed using any suitable mechanism or techniques, such as, but notlimited to, sutures or adhesives.

The prosthetic conduit 102 may be configured in any suitable manner fordelivery. In the present embodiment, the side-branch member 106 and themain member 104 are connected and placed in a compact configuration fordelivery, for example with the side-branch member 106 inside of the mainmember 104. A delivery and/or a deployment system, either wholly or inpart, may also be added to the assembled prosthetic conduit 102.

The prosthetic conduit 102 may be configured for delivery and deploymentin any appropriate manner. For example, the side-branch member 106 maybe disposed inside the main member 104 to facilitate placement (step1446). In the present embodiment, a 1.2 mm diameter stainless steel rodis inserted coaxially within the side-branch member 106. To enableeversion of the side-branch member 106, the side-branch member issuitably constrained from dilation or longitudinal compression, such asby helically overwrapping the side-branch member 106 to the rod usingporous polytetrafluoroethylene film. The overwrap suitably begins on the1.2 mm diameter rod adjacent to the distal end 306 of the side-branchmember 106 and ends adjacent to the proximal end 308 of the side-branchmember 106. In the present embodiment, since all regions of theside-branch member 106 with exception to the region encompassingside-branch stent 112 have an inner diameter larger than 1.2 mm, care istaken during the application of the overwrap film, creating lengthwisefolds and avoiding twisting of the side-branch member 106.Alternatively, to enable folding, the side-branch member 106 may becovered with an elastomeric tube of appropriate inner diameter andthickness.

The 1.2 mm diameter rod is then suitably used to push the side-branchmember 106 into the lumen of the main member 104, causing theside-branch member to evert onto itself until a desired portion, such asthe entire length of side-branch member 106, resides within the lumen ofthe main member 104. During the eversion process, the porouspolytetrafluoroethylene film may be removed as necessary. Alternatively,if an elastomeric tube is used, the tube may be of sufficient length toevert over itself, leaving a free end extending beyond the distal end ofthe side-branch member 106. During the eversion of the side-branchmember 106 into the main member 104, the elastomeric tube could beremoved via eversion in the opposite direction. Once the side-branchmember 106 is completely everted, the remaining overwrap film and the1.2 mm diameter rod may be removed.

In the illustrative embodiment, the side-branch balloon catheter 406 ispositioned within the side-branch member after the eversion process iscompleted. In an alternative embodiment, a side-branch guidewire 410 maybe positioned within the everted side-branch member 106. In such anembodiment, the side-branch balloon catheter 406 may or may not beincluded within the side-branch member 106.

In another alternative embodiment, the side-branch balloon catheter 406may be placed coaxially within the side-branch member 106, in lieu ofthe 1.2 mm diameter rod. The side-branch balloon catheter 406 may belocated at any suitable place along the length of the side-branch member106, such as at the distal end, suitably in registry with theside-branch stent 112. The side-branch balloon catheter 406 may then bereleasably attached to the side-branch member 106. With the side-branchballoon catheter 406 releasably attached to the side-branch member 106,the side-branch balloon catheter 406 in cooperation withpolytetrafluoroethylene film or any suitable mechanism may be used toevert the side-branch member 106 within the main member 104. Aside-branch guidewire 410 placed within the guidewire lumen of theside-branch balloon catheter 406 may also be included.

In yet another alternative embodiment, a guiding catheter, or adeployment tube similar to a guiding catheter, may be placed coaxiallywithin the side-branch member 106 in lieu of the 1.2 mm diameter rod. Ifthe side-branch member 106 is equipped with the side-branch stent 112,the guiding catheter or tube may be positioned such that its distal endabuts the proximal end of the side-branch stent 112. When so positioned,the side-branch stent 112 may be configured with an inner diameterapproximately equal to that of the guiding catheter or deployment tube.In such an arrangement, the guiding catheter or deployment tube mayprovide a well-defined passageway for other devices and may aid in theextension of the side-branch member 106. Alternatively, with the guidingcatheter or deployment tube positioned as described, the distal end maybe releasably attached to the graft component, for example by anadhesive, thermal bond, or other suitable method.

Regardless of how the guiding catheter or tube is positioned within theside-branch member 106, once it is in the desired location, the processof everting the side-branch member into the main member may be completedby using the guiding catheter or tube in cooperation withpolytetrafluoroethylene film or any suitable mechanism. If additionalsupport is required during eversion, a rod for example may be placedwithin the guiding catheter or tube. Once the eversion process iscompleted, other devices may be placed within the guiding catheter ortube or within the side-branch member 106.

The prosthetic conduit 102 may further be equipped with additionaldelivery system and/or deployment system components, or may otherwise beprepared for delivery and deployment. For example, the side-branchballoon catheter 406 may be inserted coaxially within the distal end ofthe side-branch member 106 and releasably attached to the side-branchmember 106. Further, the prosthetic conduit 102 may receive the mainballoon catheter 400 or be placed within a constraining sheath 902. Forexample, the prosthetic conduit 102 may be suitably folded into acompact configuration and placed in a constraining sheath 902. The pushtube 900 may then be placed within the constraining sheath 902. Ifrequired, the side-branch balloon 406 may be removed during the foldingprocess, and repositioned when convenient. Any suitable arrangement of aconstraining sheath 902, push tube 900, side-branch balloon 406, andother components may be employed. In some embodiments, particularly ifthe push tube 900 is adapted to extend within the main member 104, theprosthetic conduit 102 and the push tube 900 may be arranged prior toplacement within the constraining sheath 902.

The various embodiments of the present invention may be delivered andinstalled by any known method, using any combination of devices. Forexample, the delivery system may comprise any combination of suitableintroducer sheaths, guidewires, balloon catheters, guiding catheters,deployment tubes, constraining sleeves, push tubes, and/or any otheraccessory in any suitable arrangement.

EXAMPLE

To demonstrate the characteristics of a preferred embodiment of acircumferentially distensible tube, a 1.2 mm inner diameter film-tubewas created using essentially the same process as described above. A230×45 mm rectangular piece was cut from Solupor 7P03A microporouspolyethylene film and wrapped around the circumference of a 4 mm outerdiameter stainless steel mandrel. With the wrapping complete, both endsof the 230 mm long wrapped film section were secured to the mandrel withwire. Porous polytetrafluoroethylene film was helically wrapped over the230 mm long wrapped film section, covering the section entirely. The 4mm mandrel was then placed in an air convection oven set at 143° C. for7.5 minutes and subsequently removed and allowed to cool. Once cool, thehelically wrapped porous polytetrafluoroethylene film as well as thesecuring wire were removed and discarded. The resulting 4 mm innerdiameter polyethylene tube was then removed from the 4 mm outer diametermandrel and cut into two equal lengths.

Next, pen marks were placed on one of the 4 mm inner diameterfilm-tubes, and the film-tube was secured to a sliding mandrelmechanism. In this instance, the sliding mandrel mechanism had a 1.1 mmdiameter rod. The entire assembly was heated in an air convection ovenset at 150° C. for one minute, and the film-tube was then carefullystretched until the interval between the two pen marks (originallyspaced at 70 mm) was approximately 141 mm. The stretching caused thefilm-tube to reduce in diameter, substantially contacting the 1.1 mmrod. The film-tube was then allowed to cool and removed from the slidingmandrel mechanism.

The film-tube was then manually distended over 3.8 and 4 mm outerdiameter tapered mandrels. The approximate lengths separating the twopen marks on the film-tube while on the 3.8 and 4 mm outer diametertapered mandrels were 85 and 80 mm respectively. With the distentioncompleted, and the film-tube removed from the 4 mm tapered mandrel, thefilm-tube was secured to the linear slide and stretched until thedistance between the two pen marks was approximately 154 mm. With thestretching complete, the film-tube was allowed to remain clamped withinthe linear slide mechanism for at least of 5 minutes at ambienttemperature.

The film-tube was then manually fitted coaxially over a 1.2 mm diameterstainless steel rod. The processing of the film-tube was then completedfollowing the steps as previously described. As previously discussed,the small corrugations were formed within the finished tube, tending toallow the tube to be bent without kinking. Additionally, the completedfilm-tube was readily circumferentially distensible without significantlength change (foreshortening) and without significant diameter changepost distention (recoil). The 1.2 mm inner diameter film-tube wascapable of circumferential distention to an inner diameter ofapproximately 4 mm.

To provide comparative data, a nondistensible film-tube was created. Thenondistensible film-tube was made with approximately the same number offilm layers and the same film used to make the 1.2 mm circumferentiallydistensible film-tube above, but was not processed to render itcircumferentially distensible or to exhibit enhanced flexibility.

More particularly, a 200×17 mm rectangular piece of Solupor 7P03Amicroporous polyethylene film was cut and wrapped around thecircumference of a to 1.5 mm diameter stainless steel rod. In this case,the circumference of the 1.5 mm rod was approximately 4.7 mm, so toachieve an approximate film thickness of three layers after wrapping,one side of the rectangular piece was cut to a dimension of 17 mm,providing approximately 3 mm extra film length for overlap. With thewrapping complete, both ends of the 200 mm long wrapped film sectionwere secured to the rod with wire and the section was helically wrappedwith porous polytetrafluoroethylene film. The 1.5 mm rod was then placedin an air convection oven set at 143° C. for 3 minutes and subsequentlyremoved and allowed to cool. Once cool, the helically wrapped porouspolytetrafluoroethylene film as well as the securing wire were removedand discarded. The 1.5 mm inner diameter polyethylene tube was thenremoved from the 1.5 mm diameter rod. The 1.5 mm inner diameterpolyethylene film-tube did not possess any significant circumferentialdistensibility, nor did it possess any enhanced flexibility. If desired,however, enhanced flexibility may be imparted to such non-distensibletubes by following process steps similar to those previously describedfor helically wrapping, warming, and longitudinal compression.

The distensibility characteristics for the distensible and thenon-distensible tube were measured for comparison. A 16.5 mm longsection was cut from the 1.2 mm inner diameter circumferentiallydistensible film-tube. The section was distended slightly by fitting itcoaxially over a 1.5 mm diameter rod. The 16.5 mm long section of tubewas then coaxially fitted over an angioplasty balloon with a nominallength of 15 mm, and a nominal diameter of 4 mm. The distention of thetube to a 1.5 mm inner diameter was required so that the tube could beeasily placed onto the uninflated balloon without any change in length.Also, a length of 16.5 mm was utilized so as to cover the entire workinglength of the balloon such that the balloon edges (shoulders) did notinflate at a faster rate than the center. Inflation of the shoulders ata faster rate than the balloon center causes the shoulders at each endof the balloon to bulge and longitudinally compress the length of tube.Such longitudinal compression not only changes the length, but alsochanges the distensibility characteristics of the tube. This adverseinteraction is caused by a mismatch between the length of the balloonand the length of the tube being distended by the balloon. Thus, alength of 16.5 mm successfully matched the tube length to the balloonlength and avoided such adverse interactions.

With the tube fitted coaxially onto and centered along the length of theuninflated balloon, digital calipers were used to measure the outerdiameter of the tube. The balloon was then inflated at ambienttemperature using a hand-held inflation device in approximately 0.1 MPa(l atm) increments and the outer diameter of the tube was measured ateach increment until a pressure of 1.6 MPa (16 atm) was achieved. Oncethe 1.6 MPa inflation pressure was achieved and the final outer diametermeasurement was completed, the balloon was deflated and the length ofthe tube was measured again using digital calipers.

The difference between the length of the tube prior to distention andthe length of the tube after distention is the amount of foreshorteningundergone by the tube. The balloon was carefully repacked into theprotective packaging sleeve that was provided by the manufacturer andthe same test procedure and data collection were repeated on the 1.5 mmnon-distensible tube. The recorded outer diameter data were used tocreate a plot (FIG. 15) of tube outer diameter as a function ofinflation pressure.

FIG. 15 shows a plot of tube outer diameter as a function of inflationpressure for both the distensible and the non-distensible tube. Thedistensible tube generally increases in diameter with increasinginflation pressure. The diameter increase tends to reduce once the tubehas reached outer diameters above approximately 3.75 mm, signifying thatthe tube is approaching the maximum amount of distention that can beachieved without the application of extremely high inflation pressures.The distensible tube reaches an outer diameter of approximately 4 mmunder 1.6 MPa (16 atm) inflation pressure.

FIG. 15 includes outer diameter data for the balloon catheter only.These data are provided within the instructions for use of the ballooncatheter, and are included in FIG. 15 to show that the outer diameter ofthe balloon catheter alone (as a function of inflation pressure) isgreater than that of the distensible tube during distention by theballoon catheter. Thus, the distensible tube is limiting the outerdiameter of the balloon catheter during inflation. Note that the dataprovided within the instructions for use of the balloon catheter rangeonly from 0.2 to 1.6 MPa (2 to 16 atm). FIG. 15 also shows thedistensibility characteristics of the non-distensible tube. The diameterof the non-distensible tube remains fairly constant and is relativelyunchanged by the inflation pressure imparted to it via the ballooncatheter.

Prior to distention, as stated above, the length of the distensible tubewas 16.5 mm. The length of the distensible tube after distention wasmeasured to be approximately 15.7 mm, resulting in approximately 0.8 mmof foreshortening. Dividing the 0.8 mm foreshortening value by the 16.5mm length prior to distention, and converting to a percentage yields aforeshortening percentage of approximately 4.8 percent. Similarly, thelength of the non-distensible tube after distention (although the tubedid not actually undergo a substantial change in diameter) was measuredto be 16.1 mm, yielding a foreshortening value of 0.4 mm orapproximately 2.4 percent. In the case of the non-distensible tube, thechange in length was apparently due primarily to the shoulders of theballoon bulging against the ends of the tube and causing the slightlength reduction.

To determine the recoil characteristics of the distensible 1.2 mm innerdiameter tube, the tube was carefully fitted over a 1.5 mm diameter rod,causing a 25% increase in diameter. The tube was then removed from therod and left undisturbed for 30 minutes. After the passing of 30minutes, the tube was pushed back onto the 1.5 mm rod by carefullygrasping one end of the tube and pushing the other end of the tube ontothe rod. An approximately 6 mm length of tube was pushed onto the 1.5 mmdiameter rod before the tube buckled and could be pushed onto the rod nofurther. Because the tube could be fitted onto the 1.5 mm rod at leastpartially, there is indication of little to no recoil (or change indiameter).

The same tube is then studied for flexibility or kink resistance. Thetube was carefully wrapped around the circumference of an 11 mm outerdiameter mandrel with no indication of gross buckling of the tube. Thetube was then released from the mandrel, and rather than returning toits original substantially straight configuration, it remained curved,in a semi-circular shape having a radius of approximately 15 mm. Toprovide comparative data, a length of the 1.5 mm non-distensible tubewas wrapped around the circumference of the same 11 mm outer diametermandrel. The non-distensible tube exhibited various points where kinking(gross buckling) occurred. When released from the mandrel, thenon-distensible tube returned to a substantially straight configuration.

To further demonstrate the recoil characteristics of the distensible 1.2mm inner diameter tube, a new length of tube was tested, in a mannersimilar to that described above. In this case, rather than distendingthe tube 25%, a length of the tube was distended over the 4 mm taperedmandrel. The tube was then removed from the tapered mandrel and leftundisturbed for 30 minutes. After 30 minutes, attempts were made to pushthe tube onto a 4 mm (non-tapered) mandrel by carefully grasping theundistended end of the tube and pushing the distended end of the tubeonto the mandrel. The tube, however, having undergone some recoil, didnot fit onto the 4 mm mandrel.

Similar attempts were then made to coaxially fit the tube onto a 3.8 mm(non-tapered) mandrel. The section of the tube, which was distended to a4 mm inner diameter, fit over the 3.8 mm mandrel easily, indicating thatthe inner diameter of the tube was then approximately 3.8 mm. Thus, thedistended diameter of the tube was 4 mm and the recoil diameter of thetube was approximately 3.8 mm, resulting in a recoil value ofapproximately 0.2 mm. Dividing the approximate recoil value of 0.2 mm bythe distended diameter of 4 mm, and converting to a percentage yields apercent recoil value of approximately 5 percent.

Accordingly, a prosthetic conduit according to various aspects of thepresent invention may be suitable for the treatment of both aneurysmaland occlusive vascular disease within coronary and peripheral bloodvessels, as well as within the neurovasculature, and various otherbodily conduits. The prosthetic conduit facilitates endoluminallytreating aneurysmal vessels while maintaining normal blood flow to aside-branch vessel originating along the length of the aneurysm. Thus,the prosthetic conduit tends to alleviate the potential for ischemiccomplications in other bodily locations, and also tends to inhibit thesituation of retrograde blood flow through the side-branch vessel,facilitating the aneurysm exclusion process. The prosthetic conduit alsoprovides, by virtue of the graft material, a physical barrier thatimpedes reproliferation of disease into the lumen of the treated bloodvessel. Moreover, the prosthetic conduit provides a preformed bifurcatedjunction, obviating highly accurate placement as required during theformation of a bifurcation using two stents. The prosthetic conduitincluding the main member and side-branch member grafts also tends tocontrol redistribution of plaque at the side-branch and reduce thechance of inadvertent blockage due to plaque movement.

In accordance with various other aspects of the present invention, theprosthetic conduit provides several advantages and characteristics. Forexample, such a prosthetic conduit may allow relative ease of sizing,and may accommodate a range of main and side-branch vessel diameters.The prosthetic conduit may also offer a high degree of flexibility,bending substantially without kinking, and thus having the ability toconform to a variety of bifurcation geometries. Additionally, theprosthetic conduit may be installed through a singular vascular accesssite. Also, the prosthetic conduit may include radiopaque markers, ormay be at least partially constructed of materials that are easilyvisualized radiographically, facilitating the installation process. Theprosthetic conduit may also be installed utilizing conventional,non-specialized tools and devices for vascular surgery, interventionalradiology, interventional cardiology, and the like.

The present invention has been described above with reference to variouspreferred embodiments. However, changes and modifications may be made tovarious exemplary embodiments without departing from the scope of thepresent invention. For example, various combinations of the main members104 and one or more side-branch members 106 may be provided. Further,various changes in the configurations of the main member 104 and theside-branch member 106, for example various combinations of stents andgrafts and various materials, may be provided. These and other changesor modifications are intended to be included within the scope of thepresent invention as set forth in the appended claims.

What is claimed is:
 1. A film-tube comprising at least 2 layers ofmicroporous polyethylene film that have been bonded together, whichfilm-tube shows no substantial circumferential distension when exposedto an inflation pressure of up to 1.7 MPa at ambient temperature.
 2. Thefilm-tube according to claim 1, wherein the film-tube comprises at least3 layers of microporous polyethylene film.
 3. The film-tube according toclaim 1, wherein the layers of microporous polyethylene film have beenbonded together by a heat bonding process.
 4. The film-tube according toclaim 3, wherein the film-tube substantially consists of layers ofmicroporous polyethylene film that have been bonded together.
 5. Thefilm-tube according to claim 1, wherein the microporous polyethylenefilm had a nominal thickness of about 50 μm before being bondedtogether.
 6. The film-tube according to claim 1, wherein circumferentialdistension measured as increase in outer diameter when exposed to aninflation pressure of up to 1.7 MPa at ambient temperature is less than10%.
 7. The film-tube according to claim 6, wherein the increase inouter diameter is less than 8%.
 8. The film-tube according to claim 6,wherein the increase in outer diameter is less than 7%.
 9. A ballooncatheter comprising a non-distensible film-tube according to claims 1-8,wherein the film-tube functions to limit increase in outer diameter ofthe balloon during inflation.
 10. A prosthetic conduit comprising anon-distensible film-tube according to claims 1-8, wherein the film-tubefunctions to limit increase in outer diameter of the conduit during use.